🚅⚡Create Optimized Trains

Performance optimization addon for Create Mod trains (Forge 1.20.1).

🔗Dependencies

This mod requires Create or Create Fabric.

• Minecraft 1.20.1
• Forge 47.1.33+
• Create Mod 6.0.8+
• Flywheel 1.0.6+ (bundled with Create)

📦Features

1. LOD (Level of Detail) for Trains

• FULL — Real carriages with full physics (player nearby)
• MEDIUM — Simplified physics, normal rendering
• LOW — No physics, no collisions, minimal contraption updates
• GHOST — Ghost entity, no rendering, abstract data only

2. Carriage Grouping / Abstraction

• Merges multiple carriages into a single logical entity (TrainGroup)
• Stores only: length, speed, position, carriage list as NBT
• Expands back when the player approaches

3. Safe Multi-threading

Secondary thread (safe):

• Route calculation
• Collision prediction
• Schedule optimization
• Priority management
• LOD decisions
• Predictive simulation

Main thread (required):

• Actual entity movement
• Create physics
• Rendering
• Block interaction

4. Tick Throttling (Partial Updates)

• FULL: every tick
• MEDIUM: every 3 ticks (configurable)
• LOW: every 8 ticks
• GHOST: every 20 ticks

5. Render Optimization

• Disables animations for distant trains
• Skips full rendering for GHOST LOD
• Reduces particles and visual effects
• Hides internal details when not visible

6. Proxy Entities

• Lightweight entity representing the entire train
• Replaces dozens of contraptions
• Keeps position, speed and direction
• Recreates real carriages when needed

7. Smart Chunk Loading Management

• Loads only essential chunks
• Unloads chunks behind the train earlier
• Pre-loads chunks ahead
• Anti-thrashing (prevents repeated load/unload cycles)

8. Physics Optimization

• Simplified physics for distant carriages
• Disables collisions between carriages at low LOD
• Reduces bogie checks
• Disables internal contraption physics when far away

9. Networking Optimization

• Sends updates only when speed/direction changes
• Batches packets (delta compression)
• Reduces sync frequency for distant trains

10. Priority System

• Priority by type (EXPRESS > PASSENGER > FREIGHT > LOW)
• Conflict resolution at junctions
• Track segment reservation
• Async conflict analysis

11. Dynamic Performance Monitor

• NORMAL (TPS >= 18): full fidelity
• DEGRADED (15 <= TPS < 18): light optimizations
• CRITICAL (TPS < 15): aggressive optimizations, reduced LOD distances

🏅 Technical Performance Certificate

Create Optimized Trains has undergone a series of internal and community tests, including:

Stress Tests

• Trains over 300 blocks long
• Simultaneous moving contraptions
• Rendering with hundreds of entities
• Worlds with aggressive preloading

Compatibility Tests

• Create
• Steam ’n’ Rails
• Embeddium
• Radium
• Copycats+
• Distant Horizons

Community Testing

Pre-release versions were made available on the official Discord, ensuring that every public update is stable and free of regressions.

⚙️Configuration

File: create_optimized_trains-common.toml

All features are individually configurable with distances, intervals and toggles.

🪄Backported Fixes from Create 6.0.9+

Create 6.0.9 (for Minecraft 1.21.1) introduced several important fixes that were never backported to 1.20.1. Since 1.20.1 is no longer receiving updates from the Create team, this mod backports the following fixes for users staying on 1.20.1:

Contraption Collision Box GC Pressure (#6902)

Original problem: When train doors open/close at a station, gatherBBsOffThread() combines ALL block collision shapes into a single VoxelShape using Shapes.joinUnoptimized() — an O(n²) operation that creates massive temporary objects. The garbage collector can't keep up, causing lag spikes of 1-30+ seconds depending on train complexity.

Our fix: ContraptionCollisionMixin replaces the collision gathering algorithm with the same O(n) approach used in Create 6.0.9 (commit 8f30c2c). Instead of joining VoxelShapes, it collects AABBs directly from each block's collision shape — no intermediate allocations, no GC pressure. Also includes related duplicates: #4607, #5685, #9026, #9389.

Train Stutter from carriageWaitingForChunks

Original problem: In Train.tick(), when a carriage enters an unloaded chunk, Create sets carriageWaitingForChunks which forces speed = 0 until the chunk finishes loading. On maps with many trains and limited view distance, this causes 0.5-1.5 second freezes every time a train crosses a chunk boundary.

Our fix: TrainMixin redirects all reads of carriageWaitingForChunks in tick() to always return -1, so speed is never zeroed. Combined with the Smart Chunk Loading system (pre-loading chunks ahead of the train), trains move continuously without stutter.

Collision Check Performance

Original problem: collideWithOtherTrains() runs every tick for every train, which becomes expensive on maps with 20+ trains.

Our fix: TrainMixin throttles collision checks adaptively based on server performance — every 4 ticks normally, every 8 when degraded, every 12 when critical. Each train's check is offset by its UUID hash to distribute the load evenly across ticks.

💚About us

Publisher: GreenToastSoftware Games® (C)GreenToastSoftware Corporation. All rights reserved 2020-2026.